Before transfusing blood or a collected blood component to a recipient in need of the component, it is often desirable to minimize the presence of impurities or other materials that may cause undesired side effects in the recipient. For example, because of the potential of possible adverse reactions in the recipient, it is generally considered desirable to reduce the number of leukocytes in blood components before transfusion. Reduction in the concentration of leukocytes is often referred to as “leukoreduction”.
Filters are widely used to accomplish leukoreduction in blood products today. Filters typically include a filter media disposed between mating walls of a filter housing. Inlet and outlet ports associated with the housing provide flow to and from the interior of the filter. While filters are widely accepted in the field of blood collection and processing, and have generally worked satisfactorily, they are not without certain drawbacks. Passage through a filter often adds time to a blood processing procedure. Also, to ensure proper flow through the filter, there exists the need to monitor the vertical position of the container that holds the blood product being processed as well as the filter. Also, filter performance may vary between filter lots, thus adding to the unpredictability of the time required for a blood processing procedure and the uncertainty of the effectiveness of the leukocyte removal.
Thus, it would be desirable to provide a system and method that allows for more predictability in the time required to leukoreduce a blood product, eliminates the need to monitor the position of the blood source container and the flow-through filter and provides for lot to lot repeatability of the leukoreduction process.